1. Field of the Invention
The present invention is directed to a method and apparatus for coupling together a scope and an imaging device, as well as a system resulting therefrom.
2. Discussion of Related Art
An endoscope is a device, commonly used in the medical field, that may be used to view an interior cavity of a body. An endoscope typically includes an elongated shaft having a distal end to be inserted into a patient, and a proximal end having an eyepiece through which a user, such as a physician, may view the interior of the body cavity.
For some medical procedures, it is desirable to present an image of the interior of the body cavity on a display of an imaging system. For this purpose, it is known to use a coupling device to couple the eyepiece of an endoscope to an electronic image sensor of an imaging system so that the image sensor can sense the image produced by the endoscope and transmit an electronic signal representing the image to the imaging system display. The endoscope is typically sterilized prior to insertion into the patient. In addition, some technique is typically employed to ensure that the imaging system and the device for coupling it to the endoscope do not compromise the sterile environment.
FIG. 1 shows an example of such a prior art viewing system that includes four primary components: an endoscope 16 for insertion into the patient, an imaging unit 6 (connected to a monitor 46) for displaying an image within the patient's body cavity on the monitor, a coupling device 8 for coupling together the endoscope 16 and the imaging unit 6 and a sterile condom-like sheath 5 which prevents the coupling device 8 and the imaging unit 6 from contaminating the sterile environment.
Endoscope 16 includes a distal end 13 which is adapted to be inserted into the patient (not shown) to view an object 9 within a body cavity of the patient. At its proximal end, the endoscope 16 includes an eyepiece 36 at which an image of the object 9 is presented. Imaging unit 6 includes housing 15 which houses an image sensor 14. The image sensor 14 senses an image along an imaging axis 17, and converts the sensed image into an electrical signal. This signal is passed, via a cable 26, to a monitor or display 46 which presents the sensed image to a user.
Coupling device 8 is used to couple together the eyepiece 36 of endoscope 16 and the housing 15, so that the imaging axis 17 of image sensor 14 passes through the eyepiece 36 and the length of the endoscope 16. In this manner, the image sensor 14 can sense the image of the object 9 within the patient. Coupling device 8 includes a lens 20 which is movably mounted therein and a focusing mechanism 11 which may be manipulated to adjust a position of lens 20 within coupling device 8. When the coupling device 8 is mounted to the housing 15, lens 20 is aligned with the optical axis 17 of the image sensor 14 so that the optical axis 17 passes through the lens 20. By manipulating focusing mechanism 11, the focal length between the lens 20 and the image sensor 14 may be adjusted to focus the image (e.g., of object 9) that is presented at the eyepiece 36 on the image sensor 14.
The coupling device 8 and the housing 15 of the imaging unit 6 are typically not sterile. Therefore, the condom-like sheath 5 is disposed between the eyepiece 36 and the coupling device 8 to prevent the non-sterile components from contaminating the sterile endoscope 16. Typically, the sheath 5 is primarily formed from a flexible material that is not optically pure, and that would not convey a clear image from the eyepiece 36 to the image sensor 14. Thus, a window 7 of more optically pure material is typically provided in the sheath 5. When the system is in use, the window 7 is aligned between the eyepiece 36 and the coupling device 8 so that the optical axis 17 of the image sensor 14 passes through the window 7.